Explanation

Correct Answer: B - Create an Amazon RDS MySQL DB instance with Multi-AZ functionality enabled to synchronously replicate the data.

Why this is correct:

1. Multi-AZ deployment in Amazon RDS provides synchronous replication to a standby replica in a different Availability Zone.
2. Minimizes data loss: Multi-AZ uses synchronous replication, ensuring that every transaction is committed to both the primary and standby instances before the transaction is considered complete.
3. Stores every transaction on at least two nodes: The Multi-AZ configuration maintains a standby replica in a different AZ that receives synchronous replication.
4. High availability: In case of primary instance failure, RDS automatically fails over to the standby replica with minimal downtime.
5. Reliable database solution: RDS Multi-AZ is specifically designed for production workloads requiring high availability and durability.

Why other options are incorrect:

• Option A: While synchronous replication to three nodes provides redundancy, RDS doesn't offer this specific configuration natively. Multi-AZ is the standard AWS solution for synchronous replication across AZs.
• Option C: Read replicas in RDS use asynchronous replication, not synchronous. Cross-region read replicas have higher latency and are not suitable for minimizing data loss in the event of primary instance failure.
• Option D: This custom solution using EC2, Lambda, and RDS is complex, error-prone, and doesn't provide the same level of reliability and automatic failover as RDS Multi-AZ. It would require significant custom development and maintenance.

Key AWS Concepts:

• RDS Multi-AZ: Provides high availability and durability through synchronous replication to a standby instance in a different Availability Zone.
• Synchronous vs Asynchronous Replication: Synchronous replication ensures data is written to both primary and standby before acknowledging the transaction, minimizing data loss.
• Automatic Failover: RDS Multi-AZ automatically detects failures and promotes the standby to primary, minimizing downtime.

This solution directly addresses the company's requirements for minimizing data loss and ensuring transactions are stored on at least two nodes through AWS's managed database service.